- Chelsea: Courtois; Ivanovic, Zouma, Terry (c), Azpilicueta; Mikel, Fabregas; Willian, Oscar, Pedro; Diego Costa.
- WBA: Myhill; Olsson, Yacob, Evans, Morrison, Brunt, McClean, McAuley, Fletcher, Dawson, Rondon.
Diego Costa has to be separated from a mob of West Brom players at the final whistle as he wags his finger in their collective faces as part of a post-match lecture.
Plenty of reaction to come on this one.
Diego Costa goes down in a heap on the edge of the box. All eyes on referee Anthony Taylor.
No dice for the hosts.
There will be five minutes added on. Is there a winner in here somewhere?
Jaws on the floor around Stamford Bridge.
Yet again their defence has been found wanting.
No-one takes command of the situation as the ball pin-balls around their box and James McClean wraps his left peg around to find the bottom corner.
Roman Abramovich looks peeved.
Kenedy is invited to have a pop as the West Brom defence stand off him 25 yards out.
And he eagerly takes up the offer, rifling a low shot just wide into the hoardings behind Boaz Myhill's goal.
This feels like a done deal. The wind has gone out of West Brom.
Cesc Fabregas - jeered in the immediate aftermath of Jose Mourinho's departure - departs to a standing ovation.
Nemanja Matic - sporting his own face mask - is on in his place.
Diego Costa still bristling with aggression and danger, sees a piledriver of a shot turned away by Boaz Myhill.
That one will have left the West Brom goalkeeper's palms stinging.
That familiar Cheshire Cat grin spreads across the face of Chelsea owner Roman Abramovich.
His side finally click in attack as Willian whips a low cross into the near post where Kenedy, fresh off the bench, is arriving at speed.
Gareth McAuley lunges in to try and block, but inadvertently turns it in off his knee.
The natives are getting restless.
Less than 20 minutes to go and the Blues could do with hunting down this winner sharpish.
Three bookings in the space of a couple of minutes.
West Brom goalkeeper Boaz Myhill has his name taken as he wastes time over a goal-kick before Chelsea counterpart Thibaut Courtois and James McClean have their names taken for a bit of push and shove silliness.
Stephane Sessegnon is on for Salomon Rondon.
Saido Berahino has the stage to himself up front for West Brom.
Things don't exactly look cordial between James McClean and Saido Berahino.
The West Brom pair have a public disagreement as Berahino's shot thumps into McClean when the Irishman wanted a subtle, slipped throughball.
Diego Costa is either going to score the winner or get sent off. Something is going to happen to him.
You can feel it.
The Spaniard is buzzing around like he has necked a quadruple espresso, crashing a rising shot into the wrong side of the side netting from a tight angle.
Claudio Yacob is saved from himself as Tony Pulis subs him off. Saido Berahino is thrown on. Maybe his pace can further unsettle the unsteady John Terry.
Darren Fletcher will slot back into defensive midfield.
Willian clumps the resulting free-kick over the top as he attempts to exact his own punishment for Claudio Yacob's foul.
Claudio Yacob has got away with one here.
Chasing back after a Chelsea counter attack, the West Brom man has a tug and trip at Diego Costa as the Blues striker breezes past him.
They both tumble. Chelsea want a second yellow. Anthony Taylor holds fire once again.
Diego Costa is the epicentre of some very stormy scenes up in the West Brom box.
The Chelsea man has just had a cheap-shot nibble at Boaz Myhill, pushing the West Brom goalkeeper as he collected a cross.
An absolute dead-head of a foul and he is lucky that the referee rightly ignores West Brom's appeals for a second yellow card.
This Chelsea defence is still suspect.
Salomon Rondon is allowed too much space from a simple throw-in and is able to slap a volley across the face of goal.
He does not catch it clean, but the ball sits up nicely on the bounce for James McClean and Thibaut Courtois is grateful that his nod is straight into his gloves.
Ugly stuff from Diego Costa.
The ball runs away from the Spain international and, in frustration, Costa dives two footed after it, ploughing into Craig Gardner.
A deserved yellow.
The advertising hoardings behind the West Brom goal are displaying a message from the Premier League respect campaign - "Get on with the game" it reads.
I wonder if Peter Scudamore is hoping it might have a subliminally calming effect on Diego Costa.
We are back under way.
Chelsea make a change with the ineffectual Pedro replaced by Brazilian youngster Kenedy.
It has been more even than you might have expected from the first 10 minutes.West Brom are giving as good as they are getting.
The half ends with Diego Costa in full rage.
Anthony Taylor blew for the break just as Costa and a team-mate raced downfield on a swift counter.
West Brom were short-staffed at the back and it could well have been a chance for a Chelsea second.
Three minutes added on at the end of the first half.
Diego Costa's chin is jutting and his lip is running off.
The Chelsea striker is right in Jonas Olsson's ear offering opinions and winding the West Brom defender up like a spinning top.
Referee Anthony Taylor has a word to try and cool things down as their spat descends to a bit of push and shove.
That disagreement is not going to be resolved so easily I fear.
Roman Abramovich is in position. The billionaire Chelsea owner is leaning forward to get a better view of the action.
As he might, it has been a decent ding-donger so far.
You have to have your squad number on your protective face mask don't you?
Otherwise you might accidentally pick up a prop from Phantom of the Opera in the pre-match back-stage confusion.
See you later John Terry.
Salomon Rondon drops a shoulder and swivels, leaving the Chelsea captain behind.
Rondon clatters a shot goalwards and his rasping effort is only narrowly wide of the postage stamp.
Chelsea pile forward. This match is rumbling along like a closing-time scrap in a pub car park.
Oscar sees a shot deflected behind as the hosts picks holes a flimsy West Brom defence once again.
That goal has come out of nowhere. Chelsea have been side-swiped. Maybe the shock of it will zap the home crowd into life.
There is more atmosphere on the International Space Station than in Stamford Bridge tonight.
Craig Gardner makes it look easy from 25 yards, striding forward, taking aim and firing low and precise past a full-length Thibaut Courtois and into the bottom corner.
Two mistakes from Chelsea: first Pedro gives the ball away with a bit of midfield dither, then Kurt Zouma stands off the advancing Garnder half a second too long.
Kurt Zouma is at full stretch at one end, stretching out a leg Inspector Gadget style to poke the ball out of the reach of a lurking Baggies player in the Blues box...
Chelsea are pinging the ball around nicely. That goal has settled them down.
The footballing equivalent of the onion bhaji on an empty stomach.
A red card walking?
West Brom's Claudio Yacob - who is up against footballing rash Diego Costa - has picked up a yellow card for tripping the Chelsea striker and bringing a Blues counter to an abrupt end.
More creaking in the Chelsea defence as West Brom win another aerial duel.
James McClean's header is straight at Thibaut Courtois though.
If this football lark ever get a little bit boring for him, Eden Hazard has an alternative career as a catalogue model.
The injured Belgian is beaming Blue Steel from one of the executive boxes.
From one full-back to the other.
Branislav Ivanovic gets up the right flank and is rewarded as Diego Costa pokes his backside into his marker, takes the ball on his chest and lays the ball off into his path.
A lovely low cross into the Baggies box from Ivanovic is met by Cesar Azpilicueta at the back post who turns in from all of two yards.